A novel DOPO‐containing HTBN endowing waterborne polyurethane with excellent flame retardance and mechanical properties

Abstract

A novel flame‐retardant DHTBN (hydroxyl‐terminated polybutadiene acrylonitrile modified with DOPO) with phosphorus‐containing pendant groups is synthesized based on addition reaction between the hydroxyl‐terminated polybutadiene acrylonitrile and DOPO, which is followed to prepare flame‐retarded WPU (FR‐WPU). The chemical structures of DHTBN and FR‐WPU are confirmed via 31P NMR, XPS, and FT‐IR. The mechanical properties, thermal stability, and flame retardancy of FR‐WPU are conducted a series of tests. The tensile strength and elongation at break for the FR‐WPU films first increased and then decreased with increasing of DOPO contents. The results show that the incorporation of DHTBN into the WPU backbone slightly reduces the thermal stability of FR‐WPU. However, the incorporation of DHTBN into WPU improves the flame retardancy. The TGA‐FIR and Py‐GC‐MS results indicate the gas phase flame‐retardant effect of DHTBN. Furthermore, the morphology, elemental composition, and content of residual char from the FR‐WPU exhibited condensed‐phase flame‐retardant effects on the WPU films.

Enhanced flame retardancy and mechanical properties of waterborne polyurethane based on the phosphorus and nitrogen containing polybutadiene acrylonitrile

“…The incorporation of APBDH with low level, the polar nitrile group is easy to form hydrogen bonds with the hard segments in the polymer chain; therefore, proper hard segments evenly distributed between the soft segments can enhance the physical crosslinking of hydrogen bonds. It is conducive to the increase of strength 21,40 . Meanwhile, the stereo hindrance effects caused slight damage of the crystallization of hard segments.…”

“…It is conducive to the increase of strength. 21,40 Meanwhile, the stereo hindrance effects caused slight damage of the crystallization of hard segments. It is in favor of the toughening effect and reinforcing effect by the incorporation of the APBDH.…”

Biomass‐functionalized graphene oxide toward waterborne polyurethane composite with enhanced flame retardancy and hydrophobicity

“…When exposed to flame, P-containing structures in DOPO derivatives and GO@PA@PDA breakdown and create not only a series of free-radical catcher (HPOÁ, PO 2 Á, POÁ) to capture the highly active free radicals (HOÁ, HÁ) formed during thermal degradation, but also phosphoric acid, polyphosphoric acid, and its derivatives to enhance matrix dehydration and carbonization. 5 In the meantime, the GO@PA@PDA nanosheets with high-aspect-ratio act as a physical nano-barrier in WPU matrix, forming a protective char shield with high stability and specific surface area, which can successfully retard heat and oxygen transport services as well as the escape of organic volatile matter, endowing the WPU with continuing to improve flame retardancy. Simultaneously, the thermal decomposition of N-containing groups in DOPO derivative and GO@PA@PDA produced noncombustible gases such as NO and NO 2 , which reduces the concentration of combustible gas (O 2 ) in the environment and thus inhibits the continuation of combustion.…”

“…DOPO-based phosphonamidates (9,10-oxa-10-phosphaphenanthrene-10-oxide) have previously been demonstrated to be effective FRs for PU. 5 In quite a while, a typical issue with conventional FRs is that low concentration FRs cannot produce a superior FR effect, and high concentration FRs might cause mechanical property deterioration, which is undesirable for some end-use applications. 6 As a result, it is critical to develop aqueous polyurethane materials with acceptable flammability and complete features.…”

P, N, Si synergistic flame-retarding water polyurethane coating with superior flame retardancy and hydrophobicity

“…In recent years, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and its derivatives, have recently attracted extensive attention due to their high ame-retardant e ciency, high reactivity, and low loading [13,14]. Wang et al incorporated hydroxyl-terminated polybutadiene acrylonitrile modi ed with DOPO into WPU to improve ame retardancy [15]. Cui et al prepared a ame retardant WPU with phosphorus (P) and silicon (Si) units using 4-DOPO-((3-hydroxypropyl) imino) methyl) phenol (PHID) as a copolymeric component.…”